8 results about "Relative phase" patented technology

A device includes a grouping of N qubits, where N is equal to two or more, and a coherent light source configured to, given selected values for a set of parameters of at least a first and a second laser pulse, the parameters selected from a relative phase shift, a laser frequency, a laser intensity, and a pulse duration: apply at least the first and second laser pulses to all qubits within the grouping of N qubits, thereby coupling a non-interacting quantum state |1 to an interacting excited state |r, such that each qubit that begins in quantum state |1 returns to the state |1 upon completion of the at least first and second laser pulses, and such that qubits in the grouping are mutually blockaded.

This provides a system and method for parallel execution of multi-qubit quantum gates. [Solution] The device includes a coherent light source configured such that, given a set of N qubits, where N is equal to 2 or greater; and selected values ​​for a set of parameters for at least first and second laser pulses, where the parameters are selected from relative phase shift, laser frequency, laser intensity and pulse duration, the first and second laser pulses are applied to all qubits in the set of N qubits, thereby coupling a non-interacting quantum state |1> to an interacting excited state |r>, and as a result, each qubit that starts in quantum state |1> returns to state |1> upon completion of at least the first and second laser pulses, and the qubits in the set are blocked from each other.

The invention discloses an SPGD laser coherent synthesis method and system based on Kalman filtering prediction, and the method comprises the following steps: S1, calculating the variable quantity of a performance evaluation function and an original gradient vector, and taking the component of the original gradient vector as a measurement value of a Kalman filter; s2, on the basis of a preset state space model, predicting a relative phase state between each path of laser and the reference laser through a Kalman filter to obtain a predicted state; s3, fusing the measurement value and the prediction state through a Kalman filter to obtain optimal estimation; and S4, calculating a voltage correction value according to the optimal estimation, updating the control voltage of each path of laser based on the voltage correction value, and returning to the step S1 for cyclic execution to realize laser coherent combination. The conversion from reaction type control to predictive type control is realized, and control lag is made up to suppress dynamic noise; dependence on a single SPGD gain parameter is reduced, gain does not need to be increased for adaptive noise, and overshoot and oscillation are avoided; and the predictable characteristic of the noise is fully utilized.

The invention discloses a phase compensation method for TF-QKD, and the method comprises the steps: carrying out the data post-processing of the (interference) detection results of phase reference light with two wavelengths, obtaining the estimation of the relative phase difference between a light source and a transmission link when two transmitting ends transmit carrier signal light, and allowing the estimation of the relative phase difference according to the estimation value of the relative phase difference. Extra phase difference caused by a light source and a link is compensated, and relative phase stability between quantum signal light is guaranteed. By means of the scheme, a real-time calculation module is not needed, the calculation burden is reduced, phase modulation for phase compensation does not need to be arranged at the detection end any more, the system can be greatly simplified, and meanwhile optical loss caused by additional phase modulation can be reduced.

The invention relates to the field of terahertz polarization detection, and particularly provides a method for obtaining a terahertz wave polarization state without an additional polarization device, and the method comprises the following steps: S1, obtaining terahertz time domain signals under different relative phases; s2, obtaining light current density according to the nonlinear tensor element of the excited material, and calculating an electric field of the terahertz wave in the horizontal direction and an electric field of the terahertz wave in the vertical direction according to the light current density; s3, synthesizing the horizontal electric field and the vertical electric field into a terahertz electric field, and fitting the amplitude of the terahertz time domain signal by using the terahertz electric field to obtain fitting coefficients A and B; and S4, determining the ellipsometry of the terahertz wave by using the fitting coefficients A and B and the relative phase, and obtaining the polarization state. According to the method, the polarization state information which is difficult to directly detect is obtained through theoretical calculation and fitting by using the terahertz time domain signal which is easy to obtain, and the accuracy of terahertz wave polarization state detection is improved while the cost is reduced.

This invention discloses a method and system for determining the current time using radio observations of multiple pulsars, comprising the following steps: S1. Correcting the deviation between the local clock time and the absolute time to within a set threshold; S2. Selecting N radio pulsars, where N is greater than or equal to 4, and continuously observing the selected radio pulsars using a radio telescope to obtain observation data; S3. Processing the observation data to generate the observed pulse profile; calculating the pulsar pulse phase φ. i S4. Calculate the standard pulse profile P k With the observed pulse profile P' k The relative phase deviation δφ between i Calculate the relative phase deviation δφ with error S5. i With phase φ i deviation Δφ i S6. The deviation δT between the telescope's local clock time and absolute time is calculated, thereby determining the absolute time. This invention eliminates the need to synchronize the local clock with the absolute time of a certain time standard. It can obtain absolute time with an accuracy on the order of tens of microseconds by analyzing observed pulsars, and significantly reduces calculation time.

A process for the generation of a second harmonic radiation from a fundamental radiation, comprising the following operating steps: providing one or more nonlinear crystals (C) that satisfy the condition of second harmonic generation (SHG) through noncritical phase matching; providing an optical phase actuator (A), positioned upstream or downstream of said nonlinear crystal (C) with respect to the main optical axis (O) of the nonlinear crystal, a step of varying one or more of said parameters of the optical actuator (A) over time by controlling the temperature of the optical actuator (A) itself, or by applying electric or magnetic fields to said optical actuator (A), determining said parameters of the optical actuator (A) for which said measured power is maximum with respect to the power measured during said plurality of measurements performed.

This application discloses an information processing method, apparatus, and device based on weak measurement technology. The method includes: encoding target information into the relative phase of a pre-prepared first quantum state to obtain a second quantum state, the second quantum state including the target information; transmitting the second quantum state through a target channel and representing the transmission result through a density matrix, including the noisy target information after passing through the target channel, wherein the target channel may exhibit optical rotation effects, random telegraph noise, amplitude damping, phase damping, or depolarization noise; decoding the second quantum state based on four pairwise orthogonal weak measurement decoders to obtain the decoding result. After analyzing the decoding result, the target information amplified by weak measurement technology can be obtained. Thus, this method can estimate the target information without resource loss, with high sensitivity and relatively high accuracy, thereby helping to effectively suppress the effects of noise and interference during transmission, thereby improving communication performance.